01:830:313 Lecture Notes - Lecture 1: Lateral Geniculate Nucleus, Cyclic Guanosine Monophosphate, Phosphodiesterase 4
12 Jul 2016
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Document Summary
Do not fire action actions- fire graded potentials. Do not fire action potentials- fire graded potentials. Chromatic- three types, each activated by different set of wavelengths (low, medium, high) Fovea- densely packed with cones and with few rods. Steps: light strikes rhodopsin, rhodopsin molecule splits, retinal binds with and activates transducin, transducin activates phosphodiesterase, phosphodiesterase destroys cyclic gmp, closes ion channel, cations no longer enter, membrane hyperpolarizes, on center pathway, dark. Both dark and light follow this path: photoreceptor bipolar cell ganglion cell. Wide dendritic field- can get info from a large field of neurons (high convergence) Lgn- small part of thalamus (lateral geniculate nucleus)- sends visual info to the visual part of the brain. 2 parts of lgn- magnocellular and parvocellular sections. Small dendritic field- can get info from a small field of neurons (low convergence) Refers to antagonistic interactions between center and surround regions of the receptive fields of photoreceptor cells in the retina.
